I’ve actually got all of her portraits from packs immediately when I was opening them while looking for new mercenaries. It’s not a big deal, however, since rare portraits are generally not that uncommon, and in the long run this reward is worth just 50 coins anyway.
Have you actually got any information that Elise’s portrait cannot be dropped from packs? Back in the day, just to be safe, I did that achievement a.s.a.p. for its own sake, even though subsequently I played with Elise competitively and fulfilled the requirement naturally, in order to avoid possible ‘whoopsies’. While opening the last batch of packs, when the new mercenaries were released, the game gave me a lot of Elise’s portraits — I’ve got all of them now, but it could have been bad otherwise.
Truly? I’ve not been in the fighting pit for a while, despite regularly reaching top ranks there previosuly… It’s been time for PvE and grinding tasks for the new mercs, besides, PvP has not been that fun lately, and I would prefer to have new mercs in a competitive shape first anyway. Besides, some of them are bugged at the moment…
But I digress, let’s get back to actually important matters.
This looks problematic. The exact amount of Trigore coins is not visible, but it appears to be in the range of fourties, meaning that this whole thing in general is not right. Even if you got Tyrael’s golden portrait from the shop instead of the base one due to a known bug (is it actually the case?), the screenshot indicates that duplicate protection has not worked.
I believe you should try contacting the customer support, the proof provided being enough to indicate a problem.
As for a possible cause, I could theorise that you got Tyrael’s golden portrait instead of his base version due to a bug, and that has somehow messed with duplicate protection, but it’s hard to tell for sure.